Prelims ask
Seven countries, north to south. Odd one out is usually Brazil or Paraguay.
South America · Young fold
Andes
- Countries
- North to south: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, Argentina.
- Length
- About 7,000 km. Exam-safe figure. Some surveys print 7,000–7,500 km.
- Orientation
- North–south, along the Pacific margin.
- Mountain type
- Young fold
- Plates
- Nazca plate subducts under the South American plate. The Antarctic plate meets the range in the far south.
- Highest peak
- Aconcagua, 6,961 m, Argentina. It is not a volcano. Ojos del Salado (about 6,893 m, Chile–Argentina) is the highest active volcanic complex.
- Rivers that rise here
- Amazon (Apurímac / Nevado Mismi, Peru), Magdalena, and many short Pacific rivers. Pilcomayo and Bermejo feed the Paraguay–Paraná system. The Argentine Colorado is a separate, smaller river.
- Climate and rain shadow
- In the subtropics the east (Amazon) side is windward to Atlantic moisture; the west is the Atacama rain shadow, reinforced by the cold Humboldt current and the subtropical high. South of about 40°S the westerlies reverse this: Chile is wet and Argentine Patagonia is the rain shadow.
Mains use
Standard ocean–continent fold belt: subduction, earthquakes and the Andean volcanic arc together. Use with the 2014 margins question and the 2021 alignment question.